It should be pointed out that the present invention relates to a sealing device with sensor for a rolling bearing which comprises: a sealing shield which is mounted between the two races of the rolling bearing itself; an encoder wheel which is arranged between the same races and the shield; and a detecting sensor which is frontally arranged in relation to the encoder wheel in order to detect the movement of the encoder wheel itself.
A sealing device of the kind described above has been described in the U.S. Pat. No. 5,969,518, in which the shield is comprised of a substantially rigid shield which is mounted inside the outer race between the encoder wheel and the sensor, and it is made of non-ferromagnetic material with the aim of not interfering with the detection of the sensor itself.
The kind of sealing device which has just been described presents, however, some disadvantages in that the sensor is assembled outside the device itself, as well as which it presents a frontal detection surface which is arranged in substantial contact with the cited shield and which is opposite the encoder wheel in relation to the shield itself. When the assembly of the sensor is carried out in this fashion, it means that the sensor itself, and above all the relevant detection surface, is exposed to polluting agents which, in combination with the slight disturbance caused by the shield, result in a deterioration in the detection capability of the device.
On the other hand, the French patent No. 2 574 501 describes a sealing device in which the shield is defined by a rigid support which is mounted on the inner race of the rolling bearing, and which comprises a rubber lining which is connected to the rigid support and which extends in contact with the outer race, and which also comprises a substantially rigid race which is supported by a rigid support and which defines with the lining housing for the sensor. While this alternative protects the detection surface of the sensor from the inside of the housing, it also represents an improvement from this point of view with regard to the previously cited American patent but it also presents the disadvantage of having a barrier between the detection surface of the sensor and the encoder wheel and also has a further disadvantage in that the sensor is rigidly connected to the inner race of the rolling bearing and with the respective fixing support, which is usually arranged outside the rolling bearing and which is connected to an element which is unrelated to the structure of the rolling bearing itself.
In fact, both the presence of a barrier between the detection surface of the sensor itself and the encoder wheel, as well as the fixing of the sensor along a non-homogenous rigid chain has an outcome, in various ways and to various degrees, on the quality of the detection of the sensor itself.